MATHEMATICAL TREATMENT OF ELECTROPHORETICALLY MEDIATED MICROANALYSIS

A new concept in reaction-based chemical analysis is introduced and th eoretically described. By utilization of the variability in electropho retic mobilities among charged species, spatially distinct zones of ch emical reagents can be electrophoretically merged under the influence of an applied electric field. Electrophoretically mediated microanalys is (EMMA) exploits this phenomenon as a basis for chemical analysis ut ilizing capillary electrophoretic systems. EMMA is described in terms of the four stages required for reaction-based analysis: (1) analyte a nd analytical reagent metering; (2) initiation of reaction; (3) contro l of reaction conditions and product formation; (4) detection of speci es whose production or depletion is indicative of the concentration or quantity of the analyte of interest. The method is illustrated by the enzymatic oxidation of ethanol to acetaldehyde by alcohol dehydrogena se with the concurrent reduction of NAD+ to NADH monitored at 340 nm. Experimental results for both substrate and enzyme determinations are shown to agree with the presented theory.